1886] “ What Might Have Been? 859 
a III. 
> But this is not the whole story. Things were not always as 
‘ they now aré. If the equilibrium in the drainage of these lakes 
___- iS now so delicate, there was a time when it was more delicate 
still, and when no man could have determined in which direction 
the outflow would ultimately go. There was a time when the - 
whole northern part of the continent was covered with ice. As 
the climate grew warmer this great ice-sheet drew back. Its 
edge retreated northward slowly exposing the underlying ground. 
_ In this way Lake Erie and adjoining country were step by step 
freed from their icy covering. When the ice had melted suffi- 
ciently the Niagara river began to flow. Into all the details of 
its early course I cannot enter. Many of them are still uncertain. 
_ Butthere came a time when the level of Lake Ontario was low- 
ered sufficiently to allow the water to pass into it from Lake, 
Erie. Then the Niagara river was born and the direction of the 
lake drainage established. Then began the flow of the most 
_ beautiful river of the continent, the St. Lawrence, with its clear 
green water, seldom sullied, and its almost unvarying level both 
in summer and winter. 
Now there is ample evidence that in former days the level of = 
the Niagara river was much higher than it now is. Professor _ 
Lyell in his “ Principles of Geology,” the existence on Goat 
island and at various points along the river of alluvial strata con- _ 
taining recent shells. Terraces consisting of this material skirt 
fifty feet above the water. The fineness and softness of these: 
r ing water. The highest beds are nearly on a level with the sur- 
face of the. lake, and they were of course at the bottom of the > 
water at the time of their deposition. Hence it may be inferred — a 
“uggish stream must have extended northwards along the pres- 
Sat channel of the Niagara, of course before the excavation of z 
Mie Sorge or the full development of the cataract. Considering 
= fact we are compelled to ask where was the dam that held — 
Pack the waters so that they were able to deposit sediment so far y 
Hall has pointed out in his “ Geology of New York,” and Sir C, ` 
‘he stream for a long distance, and rise in some places forty or © = 
‘ oO deposits shew that they were laid down in still or slowly flow- 3 - 
